Counterparty Risk (% Of Total Receivable For Securities Sold) (Details)	Jun. 30, 2014
Goldman, Sachs & Co. [Member]
Concentration Risk [Line Items]
% of Total Receivable for Securities Sold	29.00%
Morgan Stanley [Member]
Concentration Risk [Line Items]
% of Total Receivable for Securities Sold	21.00%
CS First Boston [Member]
Concentration Risk [Line Items]
% of Total Receivable for Securities Sold	18.00%